Method of forming finned tube into shapes



May 27, 1930. H. w. BUNDY 1,760,039

METHOD OF FORMING FINNED TUBES INTO SHAPES Filed Feb. 6, 1928 INVENToR.-r/y//L/ Haj/ F1' ff J BY f/wm y A A ToR EYS.

Patented May 27, 1 930 UNI-TED STATES PATENT' or-rflcr.

-HBBY W. BUNDY, Ol' DETROIT, IIICHIGAN, ASSIGNOR, BY MEBNE ABSIGNmTB, TOBUNDY TUBING conm, OI DETROIT, MICHIGAN, A CORPORATION OI' RICHTIG-LII'METHOD Ol' I'OBKING FINNED TUBE INTO SHAPRS Application led Iebruary 6,1928. Serial No.l 252,222.

This invention relates to a method of forming finned tube into shapes.-

Finned tubing is advantageous for the purpose of heat exchange. Suchtube can be used in heating radiators, radiators for the cooling systemfor internal combustion engines, and one of the later uses for such tubeis for condensing units for mechanical refrigerators.

A iinned tube, however, and especially a finned tube where a helicalfinis sealed to the tube, or adjacent convolutions thereof sealedtogether, as by means of ealing metal such as so der, does not possessgood bending uahties, but offers material resistance to eing bent or:formed into suitable shapes for the purpose of being used in heatexchanging units.

Accordingly, the present invention contemplates a method by means ofwhich finned tubing can bev easily and nicely formed into any desiredshape and then set in this shape. The invention contemplates the makingup of a finned tube b leaving the parts thereon unscaled or not ound toether, and while in this condition the .tube 1s shaped as desired andthen the parts are sealed. By sealing the -tube at this time the tubeper se 1s completed and also it is set into the shape into which it waspreviously formed.

lu the accompanying drawings: Y

Fig. 1 is a side elevation of a coiled finned tube showing one shape inwhich the finned tube may be formed .for use in a condenser unit for amechanical refrigerator.

Fig. 2 is a view partly in side elevation and partly in section showinone form of iinned tube which can be treate in accordance with thisinvention.

Fig. 3 is a diagrammatical view illustrating one manner in whichpreviously shaped tube can be subjected to a bath of sealing metal.

Fig. 4 is a view illustrating another shape into which the tube may bebent.

Fig. 5 is a view partly in side elevation and partly in sectionillustrating another kind of tube which can be used in following themethod.

One form of finned tube which may be sirable shape to fit the needs towhich it is to be put. It may be shaped into the form of a spiral coil,as shown inv Fig. 1; itmay have a circular shape, as indicated in Fig.3;

vor it may have a U-shape as illustrated in Fig. 4. Any one of amultiplicity of shapes caii be used. The tube is quite easily shaped ducto the fact that the adjacent convolutionsV are not sealed together.After the length of finned tube is shaped as desired, it is thensubjected to a bath of sealing metal such as solder. This may beaccomplished by dipping the tube into molten metal 4 contained in a tank5. When the tube is bent into relatively simple shapes, as illustratedin Figs. 3 and 4, it can be held by hand during the dlpping. Where,however, more complicated shapes are desired, which may involverelatively sharp curves, suitable guide devices or braces of anydesirable character can be used. i

'When the shaped tube is thus subjected to the bath of sealing metal, itwill be noted that two things are accomplished. One is the completionofthe tube per se; in orderY to make a tube constructed as shown in Fig.2 fluid' tight, the overlapping convolutions must needs be sealedtogether. It is well understood by those versed in the art that moltensealing metal finds its way in between the overlapping parts. The otherthing accomplished is, the shaped tube is given a set. In other words,after the tube has been subjected toits bath of sealing metal and thenremoved, the finned tube retains its shape upon the cooling of thesealing metal.

Preferably, when the length of shaped tube is thus dipped, the tube issomewhat longer than necessary so as to provide portions which extendout from the bath by means of which the shaped tube can be handled.These ortions can be cut of and' then part of the he ical fin removedadjacentl the end to permit of attaching of suitable fixtures thereto.

Another kind of tube which can be shaped in accordance with thisinvention, is shown in Fig. 5 wherein a preformed tubular body 6 is usedand upon which is wound linl stock an gular in section, one leg of theangle forming a helical fin 7 and the other forming a helical band 8lying directly on the preformed tube..

This tube can be nlcel bent and shaped before the helical fin stoc issealed `to the tubular body, and it ,has been found that such a tube canbe bent into a curve sharper than can the tube 6 without the helical1in, because the helical iin stock reinforces the tube and prevents thesame from collapsing or buckling in a sharp angle where the curve iseffected. Moreover, as set forth in my copending application Serial No.205,593, filed July 14, 1927, .the inner tube 6 can be made of relativellight stock inasmuch as the iin stock afordys a material reinforcementtherefor. Such a tube is capable of being shaped as desired and thensubjected to a bath of sealing metal in a manner as above described.

By way of example, two forms of finned tube construction have beenshown, but it is within the invention to utilize finned tube differentlyconstructed; thus, the overlapped or helical windings of Fig. 2 need notbe sufficient to rovide a double wall such as shown, but may justsuflicient to provide overlapping surfaces for securing purposes.Moreover, the helical stock on the tube shown in Fig. 5 need not bewound so close together, but the several convolutions thereof may bespaced apart.

Claims:

1. The method of forming finned tube into.

shapes and inishin the tube which comprises, forming the ned tube andleaving the parts unsealed, forming the tube substantially into thedesired shape and then subjecting the same to a bath of sealing metal tofinish the tube by sealn the parts together and to set the tube into t eshape in which it was formed.

2. The method of forming finned tube into shapes, which comprises makinga tube hav ing a fin composed of helically wound stock, shaping the tubeinto the desired shape before the hehcal windings of the fin are sealedto the tube, and then settinthe tube and sealn the fin winding by sujecting the shape tube to a bath of sealing metal.

3. The method of forming finned tube into shapes, which comprises'makinga tube having a iin composed of helically wound stock, shaping the tubeinto the desired shape before the helical windings of the lin are sealedto the tube and while the tube can be easily thus shaped, and thendipping the shaped tube into a bath of molten sealn metal to set it intosaid shape and seal win ings to the tube.

4. The method of forming finned tube into shapes which comprises makinga tube having a iin composed of helically wound stock, sha ing the tubeinto the desired shape before the ehcal windings of the iin are sealedto the tube and while the tube can be easily thus shaped, dipping theshaped tube into a bath of molten sealing metal and then allowing thesealn metal to harden toset the tube into the said shape and finish thetube by sealing adjacent parts together. v

5. The method of formin finned tube into shapes, which comprises ma 'nga finned tube which includes a tubular bod fin thereon at least one o fw ich is'formed by helically wound strip stock, leaving parts of thefinned tube unconnected, shaping a length of this finned tube into thedesired shape, and then subjecting the same while in such shape to abath of molten sealn metal to seal the' fin to the tubular bod an to setthe length of inned tube into t e shape in which it was formed.

6. In the art of forming heat exchange devices or the like out of finnedtubin the method comprising the taking of a tu ular body with a helicafin thereonand bending the same substantiall to the shape of the deviceto be formed be ore the fin is ixedly secured to the tubular body,whereby relative sliding movement between the tubular body and thehelical fin may take place so that the finned tubular body vmay bereadily formed into curves or the like without rupture, and then afterthe device has been thus formed, fixedly securin the helical fin and thetubular body together y molten sealing metal.

7. In the art of formingv heat exchange devices or the like out offinned tubin the method comprisin the taking of a tu ular body with ahelica fin thereon and bendingA the same substantially to the shape ofthe device to be formed before the iin is lixedly secured to the tubularbod whereby relative movement between the tu ular body and the helicallin may take place so that the finned tubular body may be readily formedinto curves or the like without rupture, and then after the device hasthus been formed, tixedly securing the helical fin and the tubular bodytogether by dipping the formed device while it is retained in its form,in a bath of molten sealing metal.

8. In the art of forming heat exchange devices on the like out of finnedtubin wherein the tubing consists of a tubular bo y and the fin isfooted'so that the foot portion lies next adjacent a tubular body andcoo erates to form a strengthened tubular wall, t e method comprisingthe taking of this finned tube and bending it substantially into theshape of the device to be formed before the tubular and a 'helical' bodyand the iin are fixedly secured together, whereby relative movement maytake place so that the finned tubular construction may be readily formedin curves or the like witl1- out rupture and then after the tubularconstruction has been thus formed, fixing the fin and tubular bodyportion together and setting the tubular construction into the shape inwhich it has been formed by molten sealing metal.

9. In the art of forming heat exchange devices or the like out of finnedtubing wherein a tube is utilized having wound around its exteriorsurface fin stock L-shaped in cross section with one leg of the Labutting against the tube, the method comprising the taking of thisfinned tube construction and bending the same substantially into theshape of the device to be formed before the tube body and iin areIixedly secured together, whereby relative sliding movement between thetube body and iin may take place so that the finned tube may be readilyformed into curves or the like, without rupture, and then securing thetube and fin together and settin the same into its formed shape by theapplication thereto of a molten sealing metal.

In testimony whereof I aiiix my signature.

HARRY W. BUNDY.

